Hey I've been in your position and I still am, rank 5,800 and I can barely stream 210.. I suppose that's not terrible, but when I was at your rank I had the same problem, couldn't stream past 160 BPM. All I'm gonna say is download a shit ton of stream maps, make a stream map collection and play stream maps for at least 1 hour every day, you'll improve. As long as you have something to make up for your lack of streaming (in my case, hit accuracy and really good jumping) you should be okay.